Demineralized bone fiber implant compositions and methods for augmenting fixation in bone repair

ABSTRACT

A composition and methods of making or use thereof include a plurality of fibers forming a shape for augmenting fixation of a bone screw, or the plurality of fibers form a shape having a peg portion and a sheet portion to augment tendon to bone repair. The physical presence of the plurality of fibers provides initial fixation, while the use of an osteoinductive material provides long term enhancement of bone formation around the site of the bone screw or the tendon to bone repair.

This application claims priority to co-pending U.S. ProvisionalApplication No. 62/803,470 filed on Feb. 9, 2019 and U.S. ProvisionalApplication No. 62/901,935 filed on Sep. 18, 2019 the entire contents ofall of which are herein incorporated by reference.

FIELD OF THE INVENTION

The field of the invention relates to composition and methods of bonefiber implants made from cortical bone in which a plurality ofdemineralized bone fibers forms a shape having a peg portion and a sheetportion to augment tendon to bone repair.

BACKGROUND

The background description includes information that may be useful inunderstanding the present disclosure. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

All publications and patent applications herein are incorporated byreference to the same extent as if each individual publication or patentapplication were specifically and individually indicated to beincorporated by reference. Where a definition or use of a term in anincorporated reference is inconsistent or contrary to the definition ofthat term provided herein, the definition of that term provided hereinapplies and the definition of that term in the reference does not apply.

Worldwide, osteoporosis causes more than 8.9 million fractures annually,resulting in an osteoporotic fracture every 3 seconds. Osteoporosis isestimated to affect 200 million women worldwide—approximately one-tenthof women aged 60, one-fifth of women aged 70, two-fifths of women aged80, and two-thirds of women aged 90. Osteoporosis affects an estimated75 million people in Europe, USA and Japan. For the year 2000, therewere an estimated 9 million new osteoporotic fractures, of which 1.6million were at the hip, 1.7 million were at the forearm and 1.4 millionwere clinical vertebral fractures. Europe and the Americas accounted for51% of all these fractures, while most of the remainder occurred in theWestern Pacific region and Southeast Asia. Worldwide, 1 in 3 women overage 50 will experience osteoporotic fractures, as will 1 in 5 men overage 50.

Modern spine surgical techniques encounter difficulty in achieving andmaintaining fixation in osteoporotic vertebrae in the case of fractureand/or deformity. The bone-screw interface is typically the region mostsusceptible to loosening and failure. Many physical factors may affectthe final fixation strength of pedicle screws such as screw pitch anddiameter, yet host factors have at least as much effect. Pedicle screwshave been shown to loosen in patients with compromised bone strengtharising from renal osteodystrophy and osteoporosis. A significantportion of these cases will sustain catastrophic failure after attemptedsurgical fixation. As a result, some spine surgeons may refuse toperform stabilization surgery on osteoporotic patients with fracturesand/or severe deformities. There have been many attempts to improve theholding capacity of pedicle screw constructs in osteoporotic boneincluding the addition of various cements for augmentation and the useof novel screw designs such as expandable screws. Use ofpolymethylmethacrylate (PMMA) cement has been shown to increase pull-outstrength up to 150%. Use of cement to augment traditional pedicle screwfixation generally yields increased resistance to pullout and/or togglefailure in the cephalad-caudad direction as reported in numerousstudies, but there are associated potential morbidities such as spinalcanal extrusion or vascular flow obstruction.

A further and significant disadvantage of the use of PMMA screwaugmentation is that it is a non-biological repair that make revision orre-operation very difficult. It is a “bridge burning” procedure.

Similar problems of initial fixation strength and subsequent looseningand failure exist with the use of screws in orthopedic procedures suchas hip fractures that often occur in patients with osteoporotic orotherwise compromised bone.

Moreover, there is a desire for implants to bond effectively and rapidlyto surrounding bone, particularly when that bone is compromised. Variousstrategies are employed to facilitate this including the use of porousingrowth surfaces. Implant loosening however remains a problem andconcern to orthopedists.

When tendon or ligament tissues or grafts are placed either inapposition to bone, as in the case of rotator cuff repair or in bonetunnels as in anterior cruciate ligament repair, the creation orrecreation of the tendon-bone enthesis is a problem and concern toorthopedists.

SUMMARY OF INVENTION

The inventors have advantageously discovered a composition and method ofimproving the fixation of implants and tissue to bone through the use ofan implant, which may, for example, be composed of a plurality of fibersof demineralized bone (i.e., demineralized bone fibers (DBF), collagenfibers, synthetic polymers, resorbable fibers) and formed into anappropriate shape. The implant according to some embodiments of thepresent invention may be placed at i) the interface between the tissueand bone, or ii) may be placed in a hole of a bone prior to insertion ofa screw.

In some embodiments of the present invention, a composition and methodare provided for improving the fixation of screws in bone using a fiberimplant as disclosed herein. For example, the fiber implant may becomposed of a plurality of fibers that are formed into an appropriateshape. Using the implant, kits, and/or methods as disclosed herein, theimplant is placed in the hole in the bone to be repaired. Morespecifically, the implant is placed in the hole of the bone in which abone screw it to be placed. By placing the implant in the hole of thebone prior to the insertion of the screw, the implant contacts theimplant and provides a denser substance into which the screw may besecured, thereby increasing the insertion torque and the force requiredto pull the screw back out of the hole. As such, the implant provided inthe hole of a bone prior to insertion of a bone screw decreases thechances of the screw being able to dislodge from the hole and allows fora more secure and effective bone repair. For example, as demineralizedbone fibers (DBF) are both osteoinductive and osteoconductive, there isan additional benefit of an DBF fiber implant providing an increase inthe local bone growth around the implant and further increasing thelikelihood of a long term and possibly permanent bone repair.Additionally, other fiber forms (e.g., collagen fibers, biocompatiblepolymer fibers, and/or resorbable polymer fibers) may also beosteoinductive and/or osteoconductive. The benefits of these fiberimplants are of particular relevance when the screw is being implantedinto osteoporotic bone or into an existing screw hole, as in the case ofrevision surgery.

Notably, the inventive subject matter includes an implant for bonerepair or screw fixation, wherein the implant includes a plurality offibers forming a shape of a cylinder, a tube, a cannulated cylinder, atruncated cone, a cannulated truncated cone, a truncated cone with aflared end, or a cannulated truncated cone with a flared end, tube witha flared end, or a truncated cone shape. In preferred embodiments, theplurality of fibers are cut from demineralized cortical bone. Further,the implant has a proximal end and a distal end. For screw fixation,preferably, the plurality of fibers form the shape of a truncated conewith a flared end, a tube with a flared end, or a cannulated truncatedcone with a flared end, and the flared end is at the proximal end of theimplant. The length of the implant may be of between 1 cm and 10 cm.Preferably, the length of the implant is 4 to 5 cm. More preferably, theimplant has a length of 4 cm. The volume of the implant having a lengthof between 1 and 10 cm, may also have a volume of between 0.15 cm³ to10.0 cm³. More preferably, the volume of the implant may be of between0.15 cm³ to 2 cm³.

Typically, the flared end of the implant has an indent for receiving abone screw.

In other typical embodiments, the implant is dehydrated.

The inventive subject matter also includes methods of augmentingfixation of a screw in a bone with the implant disclosed above andherein, in which optionally a guide wire may be placed to define aposition in the bone for the screw, followed by inserting or providingthe implant to a cavity in the bone, and then inserting or providing thescrew into the implant.

Specifically, when the guide wire is used, the method includes placingthe implant on the guide wire through the cannulated, tubular, or coneshape of the implant and moving the implant along the guide wire intothe cavity, facilitating placement of the implant and also preventing ordecreasing the incidence of the implant buckling. For moving the implantalong the guide wire, a custom pusher, an awl, a tap, and/or a drill maybe used. Additionally, the cavity in the bone may be formed using anawl, a tap, and/or a drill. The formation of the cavity using the awl ortap reduces the incidence of any removal of the bone and inducingcompaction to reinforce fixation of the screw in the bone. The cavity inthe bone may be provided with additional demineralized bone fibers(DBF), biocompatible polymer fibers, collagen fibers, and/or resorbablepolymer fibers.

In preferred embodiments, the method of augmenting fixation of a screwin a bone with one of the presently disclosed implants includes placinga guide wire to define a position in the bone for the screw, therebydecreasing the incidence of buckling of the implant, inserting orproviding the implant to a cavity in the bone, and inserting orproviding the screw into the implant wherein the inserting or providingof the implant or the screw includes using a cannulated instrument or anopen-ended syringe with the implant contained therein. The implant maybe made of demineralized bone fibers (DBF), biocompatible polymerfibers, collagen fibers, and/or resorbable polymer fibers, and theimplant may be provided with additional fibers of the same or differenttype as disclosed herein. The implant made of the DBF fibers may be bothosteoinductive and osteoconductive.

The inventive subject matter also includes methods of fabricating thefiber implant. A method of fabricating the presently disclosed fiberimplant includes dispersing a plurality of fibers (DBF, biocompatiblepolymer fibers, collagen fibers, and/or resorbable polymer fibers) in afluid, wherein the fibers and the fluid are in a ratio of between about1 gram of fibers to about 3 mls to about 50 mls of the fluid, providingthe dispersed plurality of fibers with pressure into a vented moldthereby draining the fluid out of the mold. Preferably, the fibers andthe fluid are in a ratio of 1 gram of fibers in about 3 mls to 20 mls offluid. More preferably, the fibers and the fluid are in a ratio of 1gram of fibers in about 3 mls to 10 mls of fluid.

In additional embodiments, the method disclosed above and herein alsoincludes heating the plurality of fibers in the mold. Preferably, theheating occurs at or between about 35 to 55 degrees Celsius. In someembodiments, the method also includes lyophilizing the plurality offibers.

The inventors have also contemplated a kit for augmenting fixation of ascrew in a bone, wherein the kit includes at least one of the presentlydisclosed fiber implants as disclosed above and herein. The contemplatedkit may also include a guide wire, an awl or a tap, and/or a screw to beplace in the bone to be repaired. In some embodiments, the guide wire,the awl, and/or the tap are disposable.

In addition to screw fixation, the inventors of the presently disclosedsubject matter have discovered an advantageous implant for the surgicalreattachment of tendon to bone. The presently disclosed implant is atonce capable of: 1) providing an osteoinductive and osteoconductiveimplant to facilitate regeneration of the enthesis, 2) augmenting theeffectiveness of the suture anchor, and 3) self-stabilizing duringsurgery unlike other implants. Accordingly, aspects of embodiments ofthe present invention are directed to a means of improving the fixationof implants and tissue to bone through the use of an implant, which may,for example, be composed of fibers of demineralized bone, collagen,polymer, and/or resorbable polymer fibers, and formed into anappropriate shape. In particular, the implant made of a plurality offibers has a peg portion and a sheet portion. According to someembodiments of the present invention a suture anchor may be placed intothe peg portion of the implant and the suture anchor driver is then usedto hold the implant and suture anchor to allow the combination to beintroduced into the joint being treated. By placing the peg portion ofthe implant into the cavity placed to receive the suture anchor andscrewing the suture anchor into place, the sheet portion of the implantis held in the desired place on the bone bed where the tendon is beingreattached. In this way, the sutures can be used to reapproximate andtie down the tendon to effect repair. For larger repairs multipleimplants may be used.

In some embodiments of the present invention, the implant is placed atthe interface between a torn rotator cuff tissue and the bone. Theimplant according to some embodiments of the present invention serves toimprove the integration between the tendon and bone and facilitaterecreation of the enthesis.

Typical embodiments of the present invention include an implant fortendon-to-bone reattachment, the implant made of a plurality of fiberscut from demineralized bone, the plurality of fibers forming acontiguous shape having a peg portion and a sheet portion. Inparticular, the peg portion has a tubular shape with a closed end and anopen end and is capable of being inserted closed-end first into a cavityof a bone. The sheet portion has two sides, and a first side is incontact with an area on the surface of the bone adjacent the cavity. Intypical embodiments, the second side of the sheet portion contacts thetendon and the sheet portion thereby forms an interface between thetendon and the bone.

In specific embodiments, the length of the peg portion of the implant isof between about 10 to 50 millimeters (mm). The diameter of the pegportion may be of between about 3 to 10 mm.

In other specific embodiments, the sheet portion of the implant may beany shape so long as it fans out on the surface of the bone andsurrounds the open end of the cavity. For example, the overall sheetportion surrounding the region of the peg portion may be in a shape ofor similar to a rectangular, a square, a circle, or a non-perfect shapethereof and having a perimeter that forms a rectangle, a square, acircle, or an irregular shape thereof. Additionally, the sheet portionmay not form a particular polygon shape, but has a perimeter of straightsides. The straight sides may each independently have a length ofbetween 5 and 20 mm. In example embodiments, in which the sheet portionhas a circular shape, the diameter of the circular shape may be ofbetween about 5 and 20 mm. In additional or alternative embodiments, thesheet portion may have a thickness of between about 0.5 to 5 mm.

The implant made of a plurality of fibers as described herein having apeg portion and a sheet portion, may be made of demineralized bonefibers (DBF), collagen, polymer, and/or resorbable polymer fibers.Preferably, the implant is made of a plurality of DBF fibers.

The inventive subject matter also includes a method of augmentingreattachment of a tendon to a bone using the implant as disclosedherein. The method includes placing a suture anchor into the peg portionof the implant, optionally preparing a bleeding bone bed on the bone,creating a cavity in the bone, placing the peg portion of the implantinto the cavity in the bone, screwing the suture anchor into place, andusing the sutures to re-approximate and tie down the tendon to effectthe reattachment of the tendon to bone.

The inventive subject matter also includes a method for making thepresently disclosed implant. In typical embodiments, the method formaking the presently disclosed implant includes dispersing a pluralityof fibers with pressure (under pressure) into a vented mold therebydraining the fluid from the mold. The method may further include heatingthe plurality of fibers in the mold. Heating of the plurality of fibersmay occur at or between 35° to 55° or 45° to 55° C. In exampleembodiments, the fibers (e.g., demineralized bone fibers) arelyophilized.

The inventors also contemplated methods of augmenting a tendon to bonereattachment procedure in which the implant as disclosed herein isplaced between the tendon and the bone.

Additional embodiments of the contemplated subject matter include amethod of facilitating the surgical placement of an orthopedic boneimplant wherein the method includes augmenting the orthopedic boneimplant with a peg portion. The orthopedic bone implant may be anexisting sheet implant known in the art. As such, methods may includemodifying the sheet form or modifying the manufacture protocol of thesheet form to include a peg portion attached thereto.

Aspects of the inventive subject matter include an augmented implantwherein an implant (e.g., a sheet implant) is modified to have astabilizing portion. The stabilizing portion may increase theeffectiveness of sutures used to place the implant for the neededsurgical repair. Furthermore, the stabilizing portion may increase thestability of the implant while the implant is being surgically placedand/or tethered into place. For example, the stabilizing portion may bea peg portion. The peg portion may be solid or tubular (e.g., hollow)with an open and closed end.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawings will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 shows an implant for augmentation of screw fixation and deliverydevice, according to embodiments of the present invention where theimplant 1 is placed in the tubular portion of the delivery instrument 2and is expelled from the device using the plunger 3 where an optionalprotective cap 4 may be included and is removed prior to use.

FIG. 2 shows a variant of the implant 1 wherein the front of thecylinder has a domed shape 5 to facilitate insertion, according to someembodiments of the present invention.

FIG. 3 shows a variant of the implant 1 wherein the rear of the cylinderhas a central depression 6 to facilitate insertion of the screwcentrally in the implant, according to some embodiments of the presentinvention.

FIG. 4 shows a cylindrical mold 7 and plunger 8 designed to producecylindrical implants, according to some embodiments of the presentinvention.

FIG. 5 shows a variant of the mold 7 of FIG. 4 wherein the plunger 8 hasa spike 9 that produces a central depression in the implant tofacilitate central screw insertion, according to some embodiments of thepresent invention.

FIG. 6 shows a further variant of the mold 7 of FIG. 4 wherein thedistal end of the cylindrical mold 7 has a domed depression 11 toprovide a domed implant, according to some embodiments of the presentinvention.

FIG. 7 shows a mold 12 with semi cylindrical depressions 13. DBF is wetlaid into a mold and the implant is formed from two conjoined semicylindrical depressions. The implants 14 may be stored in this manner ina flexible storage tray 15 and at the time of surgery may be foldedtogether to produce a cylindrical implant 16, according to someembodiments of the present invention.

FIG. 8 shows a sheet mold 17 and sheet 18 produced from it. Thethickness and density of the sheet are controlled by varying thequantity of DBF used and the spacing between the lid and the bottom ofthe mold, according to some embodiments of the present invention.

FIG. 9 shows a sheet of DBF 19 formed onto the porous surface of animplant 20, according to some embodiments of the present invention.

FIG. 10 shows a hamstring graft 21 with a DBF sheet 22 sutured into theregions of the graft destined for the bone tunnels, according to someembodiments of the present invention.

FIG. 11 shows a sheet of DBF 22 placed between the tendon 23 and bone24. Also shown are sutures 25 a and suture anchors 25 b used to reattachthe tendon, according to some embodiments of the present invention.

FIG. 12 shows a DBF implant 26 formed in a shape that surrounds the hipstem and forms an interface between the hip stem 27 and surrounding bone28, according to some embodiments of the present invention.

FIG. 13 shows a cross sectional view of a variant of the implant foraugmentation of screw fixation 1 wherein in addition to the domed end 5to aid insertion there is an expanded proximal portion of the implant29, according to some embodiments of the present invention.

FIG. 14 shows a cross sectional view of a variant of the implant foraugmentation of screw fixation 1 wherein the implant is of a narrowerdiameter at its distal end 30, according to some embodiments of thepresent invention.

FIG. 15a shows a variant of the implant for augmentation of screwfixation 31 wherein the implant is in the form of a rectangular prism,according to some embodiments of the present invention.

FIG. 15b shows a variant of the implant of the present disclosure, wherea central portion 32 is densified to provide it with increased strength,according to some embodiments of the present invention.

FIG. 15c shows a variant of the implant of the present disclosure wherethe cross-section 33 is semi-circular, according to some embodiments ofthe present invention.

FIG. 15d shows a variant of the implant of the present disclosure wherethe rectangular prism is narrower at the center 34, according to someembodiments of the present invention.

FIG. 15e shows a variant of the implant of the present disclosure where;the rectangular prism is both narrower at the center 34 and possesses asemi-circular cross-section 33, according to some embodiments of thepresent invention.

FIG. 15f shows a variant of the implant of the present disclosure wherea side view cross-section of a drill hole 35 with an implant 31inserted, the insertion being effected by use of a pusher 36, where theimplant is longer than is required to fit the hole, according to someembodiments of the present invention.

FIG. 15g shows a side view cross-section of a drill hole 35 with animplant 31 of the present disclosure inserted, the insertion beingeffected by use of a pusher 36, Where the implant is the exact lengththat is required to fit the hole, according to some embodiments of thepresent invention.

FIG. 15h is an end view of the implant of FIG. 15c looking down the holeto show the implant forms a space-filling implant when inserted,according to some embodiments of the present invention.

FIG. 15i is a cross-sectional view of the implant of FIG. 15e in atapered hole where the shape of the implant forms a space-fillingimplant in the tapered hole, according to embodiments of the presentinvention.

FIG. 16 shows a cross-section view of an apparatus for water assistedinjection molding of DBF fibers, where the DBF fibers 37 are loaded intoa syringe 38, the distal end of the syringe is fitted into an adapter39, attached to which is a detachable mold 40, where the mold is taperedtowards its distal end and has vents 41 along its length, and aremovable vented end cap 42, and the detachable mold is removed afterDBF injection and placed into an oven or lyophilizer for drying,according to some embodiments of the present invention.

FIG. 17 shows a cross-section view of an apparatus for water jetassisted injection molding of DBF fibers, where the DBF fibers 37 areloaded into a hopper 43, the hopper being attached to a detachable mold40, the mold tapered toward its distal end having vents 41 along itslength, and a removable vented end cap 42, where the water jet 44 isactivated to force the DBF from the hopper and into the mold, and thedetachable mold is removed after DBF injection and placed into an ovenor lyophilizer for drying, according to some embodiments of the presentinvention.

FIG. 18 shows a cross-section view of a variant of the apparatus shownin FIG. 16 that provides for manufacture of a cannulated implant usingthe water assisted injection molding process. The DBF fibers 37 areloaded into a syringe 38, the distal end of the syringe is fitted intoan adapter 39, attached to which is a detachable mold 40, where the moldis tapered towards its distal end and has vents 41 along its length, anda removable vented end cap 43 that also serves to hold a guide wire 44.

FIG. 19 shows how the detachable mold of FIG. 18 is removed after DBFinjection and a cap 45 is placed on the proximal end of the devicelocating and centralizing the guide wire. The mold is then placed intoan oven or lyophilizer for drying, according to some embodiments of thepresent invention.

FIGS. 20a-20e show the steps in the surgical implantation technique tocreate a cavity for implantation of a cannulated implant. For thepurpose of the demonstration a synthetic foam analog 46 of osteoporoticbone is used (Sawbones Inc.). In FIG. 20a a guide wire 47 is placed inthe bone. In FIG. 20b a cannulated awl 48 is placed over the guide wire.In FIGS. 20c and 20 d, the awl is shown being pushed and turned into thebone to form a cavity 49 as shown in FIG. 20 e. In FIG. 20 f, the awl isthen removed and an implant 50 is selected that corresponds to the sizeof the awl.

FIGS. 21a-21i show the steps of implant placement and screw insertion.In FIG. 21a the implant 50 is shown being placed on the guide wire 47.In FIGS. 21b and 21c the implant can be seen being pushed into thecavity 49. FIG. 21d shows a cannulated pedicle screw 51 with acannulated driver 52 placed over the guide wire and used to push theimplant 50 into the cavity.

FIG. 21e shows an alternative method where the awl 48 is used as thepusher. FIGS. 21f and 21g show the screw being inserted into the bone.When the screw is fully inserted the driver 52 and guide wire 47 areremoved as is shown in FIG. 21 h. While not part of the procedure forthe purposes of illustration in FIG. 21i the screw has been removedallowing the placement of the implant 50 to be seen.

FIG. 22 shows an implant 50 cross section. The implant has a centralcannulation 53. The body of the implant 54 is a truncated cone that isnarrower at the distal end. A flared top 55 at the proximal end has adepression 56.

FIG. 23 shows the cross section of a non cannulated implant. The body ofthe implant 54 is a truncated cone that is narrower at the distal end. Aflared top 55 at the proximal end has a depression 56.

FIG. 24 shows the cross section of an implant of this invention for usein ad augmentation. The implant is a truncated cone 57 wherein thedistal end is narrower than the proximal end. The central cannulatedregion 58 is flared so that the opening at the proximal end is greaterthan at the distal end.

FIGS. 25a-25e shows a device for use in ad augmentation. In FIG. 25a thecomponents 59 of the device are two sheets of DBF. FIG. 25 b shows themslotted together to make a cruciate form 60. FIG. 25c shows the fourstrands 61 of a hamstring graft positioned within the cruciate device60. Whipstitching the graft in preparation for implantation serves tocause the sheet to conform around the outside of the graft as shown inFIG. 25d and hold it in place. One device is placed at each end of thegraft as is shown in FIG. 25 e.

FIGS. 26a-26e show a device for use in ad augmentation. In FIG. 26a thecomponents 59 of the device that are two sheets of DBF, one wider thanthe other. FIG. 26b shows them slotted together to make a cruciate form60. FIG. 26c shows the four strands 61 of a hamstring graft positionedwithin the cruciate device 60. Whipstitching the graft in preparationfor implantation serves to cause the sheet to conform around the outsideof the graft as is shown in FIG. 25d and hold it in place. One device isplaced at each end of the graft as is shown in FIG. 26 e.

FIG. 27a shows a variant of the device fabricated from two DBF sheets 62and 63 that are shaped to wrap around the tendon (not shown). FIG. 27bis a photograph of a device fabricated from a DBF sheet and FIG. 27c isa variant using a single DBF sheet that can be used with a two strandgraft.

FIG. 28a shows a device for ad augmentation fabricated from a DBF sheet64 that has four holes 65. FIG. 27b shows a device for ad augmentationfabricated from a DBF sheet 64 that has four holes 65 and four cut outs66. The four strands 61 of the graft are threaded through the holesprior to whipstitching to provide the graft ready for implantation inFIG. 28 c.

FIG. 29 shows the surgical use of the device of FIG. 24. The device 57is placed within the four strands 61 of a tendon graft before beingpulled into the tibial tunnel. An interference screw 67 is then insertedwithin the device.

FIGS. 30a-30d show a device to augment reattachment of tendon to bone.The device 68 that is fabricated from demineralized bone fibers is shownin FIG. 30 a. The device has a “peg” 69 that is intended to be placed ina hole in bone, a cavity 70 within that peg that is designed to receivea suture anchor, and a sheet region 71 that is intended to sit betweentendon and bone. In FIG. 30b a dilator 72 is shown that is intended tocreate a defect in bone to receive the device 68. The dilator has adepth mark 73 that indicates the depth of hole to be made. FIG. 30cshows a suture anchor 25 b mounted on the driver 74 used to implant it.In FIG. 30d the suture anchor has been introduced into the cavity 70 inthe device. Note that the suture anchor 25 b cannot be seen in the FIG.due to the device.

In FIG. 31a the bone 24 has been prepared to receive two devices 68. Twoholes 75 have been made in the bone. In FIG. 31b the suture anchors 25 bhave been used to introduce the devices 68 into the bone and the suture25 a has been used to re-attach the tendon 23 to the bone. The sheetregion 71 of the device is sited between the tendon 23 and bone 24.

DETAILED DESCRIPTION

Aspects of the embodiments of the present invention are directed to anapproach for augmenting bone repair and healing using demineralized bonefiber (DBF), collagen, polymer, and/or resorbable polymer fiberimplants.

In some aspects, embodiments of the present invention include fiberimplants, methods of forming fiber implants, and kits including suitablyshaped and sized cylindrical fiber implants for augmenting the fixationof screws in osteoporotic or otherwise compromised bone. This approachincludes a cylinder of demineralized bone fibers (DBF™) that may beinserted into a hole in a bone in need of repair for the implant to beplaced together with and prior to the placement of a bone screw. Thecylinder is sized to be the same diameter as the screw hole. At the timeof surgery, the presence of the device increases the torque required toinsert the screw and increases the pull out force that would be requiredto displace the screw. The additional benefit of using the DBF materialis that it is osteoinductive and will cause an increase in local boneformation around the screw providing long term enhancement of fixation.The DBF implant is placed into the hole of the bone prior to insertionof the screw.

In other aspects, embodiments of the present invention include DBF,collagen, polymer, and/or resorbable polymer fiber implants, and methodsforming DBF, collagen, polymer, and/or resorbable polymer fibersimplants, and kits including suitably formed DBF, collagen, polymer,and/or resorbable polymer fiber implants for use as an interface betweenthe bone and the ligament or tendon to be repaired. For example, a sheetof DBF may be used in the bone tunnels of a soft tissue ligamentreplacement such as an ad (anterior cruciate ligament) surgery where ahamstring or tendon autograft is fixed into a bone tunnel. Additionally,a sheet of DBF may also be used in a rotator cuff repair in which theDBF sheet is placed onto the bone bed between the bone and the tendon tobe reattached.

As used herein “implant,” “fiber implant,” “implant of the presentdisclosure,” and like terms are used interchangeably to refer to asuitably shaped fiber implant made using demineralized bone fibers (DBF)as disclosed herein and disclosed in U.S. Pat. Nos. 9,486,557 and9,572,912, and WO 2016/123583, the entire contents of all of which areincorporated herein by reference. For example, as shown throughout thepresent disclosure, suitably shaped DBF implant includes a sheet of DBF,cylinder-shaped, or truncated cone forms of DBF.

Additionally, for collagen, polymer, and/or resorbable polymer fiberimplants are made following the methods disclosed herein for DBF with asubstitution or addition of the collagen, polymer, and/or resorbablepolymer fibers. While DBF fibers are exemplified herein, these otherfiber forms may also be used to form the presently disclosed fiberimplants.

Resorbable polymers are biocompatible polymers capable of resorbing inthe body and have a physical strength to form a fiber or particle atroom temperature. Non-limiting examples of resorbable polymers includesilk, collagen (including Types I to V and mixtures thereof), andproteins comprising one or more of the following amino acids: alanine,arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid,glycine, histidine, isoleucine, lysine, methionine, phenylalanine,proline, serine, threonine, tryptophan, tyrosine and valine;polysaccharides, including alginate, amylose, carboxymethylcellulose,cellulose, chitin, chitosan, cyclodextrin, dextran, dextrin, gelatin,gellan, glucan, hemicellulose, hyaluronic acid, derivatized hyaluronicacid, oxidized cellulose, pectin, pullulan, sepharose, xanthan andxylan; resorbable polyesters, including resorbable polyesters made fromhydroxy acids (including resorbable polyesters like poly(lactides),poly(glycolides), poly(lactide-co-glycolides), poly(lactic acid),poly(glycolic acid), poly(lactic acid-co-glycolic acid),poly(dioxanones), polycaprolactones and polyesters with one or more ofthe following monomeric units: glycolic, lactic; trimethylene carbonate,p-dioxanone, or ϵ-caprolactone, and resorbable polyesters made fromdiols and diacids; polycarbonates; tyrosine polycarbonates; polyamides(including synthetic and natural polyamides, polypeptides, andpoly(amino acids)); polyesteramides; poly(alkylene alkylates);polyethers (such as polyethylene glycol, PEG, and polyethylene oxide,PEO); polyvinyl pyrrolidones or PVP; polyurethanes; poly etheresters;polyacetals; poly cy ano acrylates; poly (oxy ethylene)/poly (oxypropylene) copolymers; polyacetals, polyketals; polyphosphates;(phosphorous-containing) polymers; polyphosphoesters; polyalkyleneoxalates; polyalkylene succinates; poly(maleic acids); biocompatiblecopolymers (including block copolymers or random copolymers); andhydrophilic or water soluble polymers, such as polyethylene glycol,(PEG) or polyvinyl pyrrolidone (PVP), with blocks of other biocompatibleor biodegradable polymers, for example, poly(lactide),poly(lactide-co-glycolide), or polycaprolactone or combinations thereof.Resorbable polymers also include cross-linked polymers, and include, forexample, cross-linked collagen, as well as functionalized polymers. Insome embodiments, resorbable polymers are resorbable polyesters.

In further embodiments, the DBM, synthetic polymer, collagen, orresorbable polymer fibers may be coated (e.g., at least in part) with acalcium ion donor compound. Examples of calcium ion donor compoundsinclude calcium peroxide, calcium ascorbate, calcium sulfate, calciumphosphate, calcium carbonate, calcium chloride, and mixtures thereof.

The popularity of demineralized bone matrix (DBM)-based products isbased on the ability to induce bone formation through expression ofinherent non-collagenous proteins that stimulate some cell types presentat the graft site to differentiate into bone forming cells. Thisinduction of bone formation process is referred to as “osteoinduction”and is due to the natural presence of bone morphogenic proteins (BMPs).DBM also provides a scaffold for these cells to populate and spreadthroughout in a process known as “osteoconduction.” Demineralized bonein the form of a fiber, known as Demineralized Bone Fiber (DBF) has aphysical form that has been shown to optimize and enhance theosteoconductive performance of DBM. In some embodiments of the presentinvention, a composition and method of manufacture of DBF fibers is asdisclosed in U.S. Pat. Nos. 9,486,557 and 9,572,912, supra. When DBM orDBF is combined with osteogenic cells that are capable of forming bone,the three mechanisms of bone healing (e.g., osteoinduction,osteoconduction, and osteogenesis) are combined.

In exemplary embodiments, the DBF implant is dried so that the implanthas sufficient rigidity to allow it to be pushed into a pre formed hole.The DBF fibers may be easily formed into any of the required implantshapes using molding or wet laying processes prior to drying. Optionallya heating step may be utilized which has been shown to impart evengreater cohesion to formed DBF implants without affecting the implant'sosteoinductivity.

Variations and sophistications to the design include shaping or domingof the distal end of the DBF implant to aid in insertion of the DBFimplant into the hole of the bone. An example of such a design isexemplified in DBF implant 5 of FIG. 2. In some embodiments, theproximal end of the DBF implant may also be flared 29 in FIG. 13. Thisfeature may help prevent the implant from being pushed too far into adrilled hole. It will also provide additional DBF fibers at the cortexof the bone and may facilitate healing of that region of the bone.Reformation of the cortex of the bone is particularly important forpedicle screw fixation in spinal surgery as toggling of the screw is theprimary mode of loading and hence failure, and the cortex provides themost resistance to this mode of loading.

The implant may also be a non-uniform cylinder, i.e. a truncated cone,such that the distal end 30, as shown in the cross-sectional view inFIG. 14 is narrower than the proximal end of the implant. The implant isplaced into the hole prior to insertion of the screw.

An implant in the shape of a rectangular prism 31 as shown in FIG. 15amay also be used for augmentation of screw fixation. The rectangularprisms may be formed individually or may be cut from a sheet of material18 that has been formed in a mold. A simple rod 36 may be used to aidinsertion of the implant into a drill hole. Densification of an area 32of the implant may be done to provide a strengthened area to aidinsertion. An implant 31 in the shape of a rectangular prism with asemi-circular cross section 33 allows for more effective filling of thehole. This can be seen in FIG. 15h which is a top view of an implant 31with a semi-circular cross section 33 placed in a drill hole 35. Theimplant is placed into the hole prior to insertion of the screw.

In some instances, it will be desired to place an implant in the holecreated when a screw is removed from bone, such as in a revisionprocedure, or in a hole created by an awl. In these cases the distal endof the hole will generally be a smaller diameter than the proximal end.An implant with a shape such as is shown in FIG. 15d or 15) is designedto be used in this instance. The implant is placed into the hole priorto insertion of the screw.

While implants according to embodiments of the present invention may beeasily placed into drilled holes by hand, it is envisaged that in someinstances it may be desired to have the implant that is provided to thesurgeon to be pre-loaded into a syringe like device implant shown inFIG. 1. As is shown in this FIG., the implant 1 is held in the body ofthe syringe 2. In this embodiment, the implant includes a removable cap4 to maintain the implant in place during storage and transportation,and may optionally have a luer fitting to allow pre hydration of theimplant. For implant delivery, the distal end of the syringe is placedover the drill hole and the plunger 3 used to expel the implant. Areusable implant delivery system may also be used.

The hole to receive the implant may be formed by drilling, tapping, orby use of an awl, or may exist through the removal of a screw.

In a variant of an implant according to some embodiments of the presentinvention, the implant is provided with a hole through its length suchthat the implant may be delivered over a guide wire.

When pushing the proximal end of the implant into the hole or cavity inthe bone there is a buckling force caused by friction of the implantagainst the bone. Several factors may be incorporated into the design toaccommodate this. Firstly, the implant may be in the form of a truncatedcone with the distal end narrower than the proximal end as is shown inFIGS. 22 and 23. Secondly, an awl is used to provide the cavity in thebone that is itself in the overall shape of a truncated cone such thatthe cavity produced is the same dimensions as the implant. Thirdly anexternal device may be used to provide support and resistance tobuckling on insertion. This may be an open-ended syringe, as disclosedabove where the barrel of the syringe provides support to the implant,or it may be by placing the cannulated implant over a guide wire.

It may also be desired to prevent the implant from being displaced toodeeply into the bone. In the designs shown in FIGS. 22 and 23 the flaredtop 53 acts to prevent this occurrence.

The surgical technique for using an implant of this invention isoutlined in FIGS. 20 and 21. A synthetic analog of osteoporotic bone 46produced by Sawbones, Inc. is accepted by the FDA and others as asurrogate for osteoporotic bone. A guide wire 47 is placed in the bone.A shown in FIG. 20b a cannulated awl 48 is then placed over the guidewire. The awl is dimensional the same as the implant that is to be used.A further benefit of using an awl is that it does not remove bonetissue, but rather pushes it laterally and forms a densified bone layerthat in itself will aid fixation. In FIGS. 20c and d the awl is shownbeing pushed and turned into the bone to form a cavity 49 as shown inFIG. 20 e. The awl is then removed and an implant 50 is selected thatcorresponds to the size of the awl. Where the implant has a flared endthe awl may also have a corresponding feature.

FIG. 21 shows the steps of implant placement and screw insertion. InFIG. 21a the implant 50 is shown being placed on the guide wire 47. InFIGS. 21b and c the implant can be seen being pushed into the cavity 49.FIG. 21d shows a cannulated pedicle screw 51 with a cannulated driver 52placed over the guide wire and used to push the implant 50 into thecavity. FIG. 21e shows an alternative method where the awl 48 is used asthe pusher. FIGS. 21f and g show the screw being inserted into the bone.The guide wire serves an additional purpose in that it helps maintainthe screw trajectory in the center of the implant so that DBF is pushedlaterally around the whole screw circumference.

When the screw is fully inserted the driver 52 and guide wire 47 areremoved as is shown in FIG. 21 h.

In FIG. 21i the screw has been removed allowing the placement of theimplant 50 to be seen. As desired the DBF fibers are displaced laterallyby the screw as it is inserted. There is a further advantage oftruncated cone and flared end in that it helps to further resist anydownward migration of the implant as the screw is inserted.

Another beneficial aspect of the flared design is that a quantity of DBFcan be positioned on the surface of the bone. This is the region in forexample, the pedicle, where cortical bone is removed to gain access tothe pedicle. In use the loading on a pedicle screw tends to “toggle” thescrew and loosen it. The primary area of bone that can resist thismotion is the cortical surface so the placement of DBF where it can helpto stimulate reformation of the cortex is beneficial. If desired the awlcould be designed so that the entire flared portion of the implant ispositioned on the bone surface.

The implant can be the same length as the screw that it is intended tobe used with or it may be shorter.

Where the procedure is desired to be done using a guide wire the device,awl or drill, screw and screwdriver will all be cannulated toaccommodate use over a guide wire.

The implant may be supplied as a kit with a guide wire and awl. The kitmay also include screws. The guide wire and awl may be supplied assterile disposable single use items or may be designed to be re-usable.

The implant is dependent on having some rigidity to enable it to beinserted in the bone and as such this is best achieved by using the DBFin a dry state. Once in place in the bone the fibers will hydrate. Theeffect of this will be to cause them to swell, providing additionalfixation.

In other embodiments of the present invention, with reference to FIG.18, DBF in the form of a thin sheet 18 may also be used to act as aninterface between an implant and surrounding bone. The DBF sheet willfacilitate conformity of the implant to the surrounding bone and willsubsequently, through its osteoinductive nature, stimulate boneformation and integration of the surrounding tissue with the implant.

DBF in the form of a hydrated thin sheet may also be pressed onto thesurface of a screw or implant prior to implantation for similar effect.

DBF in the form of a thin sheet may also be used to stimulate boneformation in the bone tunnels of a soft tissue ligament replacement suchas an ad (anterior cruciate ligament) surgery where a hamstring ortendon autograft is fixed into a bone tunnel. In this usage, as shown inFIG. 10 a sheet of DBF 22 may be sutured onto the hamstring graft 21prior to implantation into the patient with the DBF positioned so thatit is in tunnel portion of the graft, and may optionally be hydrated toaid its conformity. The osteoinductive nature of the DBF material willstimulate bone to graft healing. The sheet may be simply wrapped aroundthe outside of the hamstring or tendon bundle or may be incorporated ina way that provides DBF between the individual tendons. Suture may beused to hold the DBF sheet in place and may be whipstitched in placeduring the existing graft preparation step.

It is desired to stimulate bone formation throughout the graft withinthe bone tunnel as well as stimulate the formation of the tendon boneinterface. To this end it is desirable to have DBF within the strands ofthe graft. One means of achieving this is to use two pieces of the DBFsheet and place slots in them so that they can be slotted together toform a cruciate shape. Examples of how this could be done are shown inFIGS. 25, 26 and 27. While the most common graft uses four strands thedesign in FIG. 27 c shows how simply the design can be adapted for a twostrand graft by using a single sheet of DBF.

An alternative format of the device is to use a sheet of DBF and cut orpunch holes in it that the strands of the graft can be threaded thoughas is shown in FIG. 28a and FIG. 28 b.

As an alternative method of augmentation that is particularly suited tothe tibial tunnel a cone shaped implant 57 such as is shown in FIG. 24may be placed within the four strands of the graft, as is shown in FIG.29. The interference screw is then inserted inside the implant andscrewed into place to affect fixation of the tendon

Augmentation of other tendon and bone interfaces may also be effected byuse of sheets of DBF. FIG. 11 is a diagram showing a rotator cuff repairwherein the DBF sheet 22 is placed onto the bone bed between the bone 24and the tendon to be reattached 23. The nature of the DBF sheet is suchthat conventional suture anchor fixation techniques do not need to bemodified. In FIG. 11 the repair may be seen to be affixed using thesutures 25 a together with the suture anchors 25 b.

Rotator cuff repair is generally done as an arthroscopic procedure andso the joint is inflated with saline to aid visualization. There are anumber of patch products used for reinforcement of the tendon, and whilethis is not the intended application for the DBF sheet in theaforementioned example, our sheet will be subject to similardifficulties in use that all patch products have, namely that theirbuoyancy leads to them tending to float around in the joint.Manipulation of these sheets arthroscopically is extremely difficultadding time and complexity to the surgery. This can exclude somesurgeons from being able to use the products due to the degree ofdifficulty. In some instances, sophisticated, (i.e. complex andexpensive), ancillary instruments are developed in an attempt to makethe use of sheet products easier.

Aspects of the inventive subject matter include an augmented implantwherein an implant (e.g., a sheet implant) is modified to have astabilizing portion. The stabilizing portion may increase theeffectiveness of sutures used to place the implant for the neededsurgical repair. Furthermore, the stabilizing portion may increase thestability of the implant while the implant is being surgically placedand/or tethered into place. For example, the stabilizing portion may bea peg portion. The peg portion may be solid or tubular (e.g., hollow)with an open and closed end.

Accordingly, the inventors of the presently disclosed subject matterhave discovered an advantageous implant that is at once capable of: 1)serving as a patch for the bone site to be repaired. 2) augmenting theeffectiveness of the suture anchor, and 3) self-stablizing duringsurgery unlike other implants. Accordingly, aspects of embodiments ofthe present invention are directed to a means of improving the fixationof implants and tissue to bone through the use of an implant, which may,for example, be composed of fibers of demineralized bone and formed intoan appropriate shape. In particular, the implant made of a plurality offibers has peg portion and sheet portion.

The implant device 68 shown in FIG. 30a overcomes the problemsassociated with the manipulation of sheet-like devices in the joint. Thesheet portion 71 of the device has a “peg” 69 that is formed onto it.The peg has a cavity 70 that receives a suture anchor 25 b. The surgicaltechnique by which these implants are used is that a dilator 72 or otherinstrument is used to form a cavity. A mark 73 on the dilator serves toallow the surgeon to get the desired depth of cavity. Suture anchors 25b for use in arthroscopic surgery are generally supplied pre-loaded withsuture and attached to an insertion driver 74. The peg 69 on the deviceis sized to match the dimensions of the cavity formed using the dilatorand the cavity 70 in the device is sized to receive the suture anchor 25b. The suture anchor is inserted into the cavity 70 and turned slightlyto engage the threads of the anchor into the device. This served to lockthe device onto the suture anchor. The suture anchor driver can then beused to manipulate the peg part of the device into the cavity in thebone.

The sheet or top portion of the device is sized so that when multiplesuture anchors are used that the multiple devices that are used form acontiguous sheet at the tendon bone interface. Thus, if for example thesurgeon desired a 10 mm spacing between suture anchors then the deviceselected would be 10 mm wide or would be trimmed to 10 mm wide so thatadjacent device/suture anchor combinations would form a contiguoussheet. Similarly, if a double row fixation technique were to be employedwhere there were two rows of suture anchors then the dimension of thesheet portion of the device would be sized appropriately such that anon-overlapped contiguous sheet were formed.

FIG. 31b shows the first steps in the surgical technique. The surface ofthe bone where the tendon is to be re-attached 75 is treated with a burror similar to form a bleeding bone bed to maximize healing potential, asis normal practice. A dilator, or similar (not shown) is used to producecavities 76 to receive the device 68 and suture anchor. As describedabove the suture anchor is inserted into the device 68 and rotated toengage the anchor threads into the device and lock the two together. Thedevice is inserted into the cavity 76 and pushed down to fully seat it.The suture anchor is then screwed in. The anchor driver is removedleaving the sutures ready to be used. Additional anchors and devices areinserted, as required by the size of the tear being repaired. The deviceis held in place by the suture anchor and the completion of the surgeryrequires no additional manipulation of the device. To complete therepair, the current procedure of passing the sutures through the tendonand using them to reapproximate the tissue before knot tying is done.The device is sandwiched between the tendon at the bone where it canhave the desired effect of stimulating an improved enthesisregeneration.

The preferred embodiment of this device is dried or lyophilized. In thisform the device is stiff and insertion into the cavity is easiest.

An additional benefit of the device 68 is that the peg portion of thedevice serves to augment the fixation strength of the suture anchor.This is especially important when the patient's bone quality is poor. Itmay also allow the surgeon to use a smaller diameter suture anchor.

The peg portion of the device 68 is designed to be compatible with thesuture anchor it is to be used with. As such the length of the pegcorresponds to the depth of the cavity required for the suture anchorand may vary from 10 to 50 mm. Similarly, the diameter of the pegcorresponds to the diameter of cavity required for the suture anchor andmay vary from 3 to 10 mm.

The sheet portion 71 of the device is sized such that when a multitudeof suture anchors are used that the bone bed 76 is fully covered. Thismay be achieved by the surgeon trimming devices to the required sizeprior to use, or by selection of the appropriate size from an availablerange of product sizes. The sheet portion may be rectangular, square orround. For square and rectangular devices the side dimensions will varyfrom 5 to 20 mm. For round devices the sheet portion will be 5 to 20 mmin diameter. The thickness of the sheet portion of the device will varyfrom 0.5 mm to 5 mm.

By using the suture anchor as the delivery device for the implant theneed for additional instruments is avoided. The design, by using theanchor hole to provide initial fixation of the device, provides a verysimple means of introduction of a sheet device, and of holding it in thedesired place without the need for any additional instruments, oradditional portals into the joint.

By sizing the top portion, or sheet, of the device to be compatible withthe spacing used between suture anchors the need for multiple sizes ofdevice is avoided. This additionally means that the waste associatedwith cutting larger sheet implants to the desired size is avoided.

While this modular approach to covering the enthesis is preferred, ifdesired a larger sheet implant could be provided that had one or twopegs.

While the examples given for use of this design were for rotator cuffrepair it will be understood by one skilled in the art that theapplicability is more general than this and is applicable to anyinstance of tendon to bone reattachment or repair, or any instance wherea sheet implant needs to be held in place during surgery. Accordingly,the inventors further contemplate augmenting any sheet implant with apeg portion to thereby facilitate the surgical placement of the implant.It is contemplated that any existing sheet implant may be improved bymodifying an already manufactured sheet implant or by modifying themanufacturing protocols of the existing sheet implant to incorporate apeg portion to produce an implant having improved stability duringsurgical placement.

In some embodiments of the present invention, a DBF sheet may be usedfor augmentation of bone-to-bone repair either in a primary fracturerepair or in a procedure to remedy a non-union. In these instances, theDBF sheet will form a malleable interface between the two (or more) bonefragments.

A DBF sheet may also be wrapped around the periosteum to hold bonefragments or graft in place in traumatic fractures and may act as aperiosteum substitute. The osteoinductive and osteoconductive nature ofthe DBF sheet will facilitate healing.

In many joint replacements a stem is placed into a cavity created in theintramedullary canal. It is often desired to enhance the integration ofimplants such as total hip or shoulder replacements to the surroundingbone. DBF may be formed into a sheath 26 that conforms to the shape ofthe implant stem 27. The DBF may then provide for augmentation, orstimulation of fixation, of the stem to the surrounding bone.

A further issue that may occur is that, particularly in the case ofrevision surgery, there is insufficient bone and the surgeon may requirethe use of bone graft. In these instances, the DBF sheath may beprovided in a range of thicknesses up to several mm in thickness toprovide for use as a bone graft substitute.

In some embodiments of the present invention, the sheet form of DBF maybe used to augment the fixation of tibial tray and acetabular cupcomponents of joint replacements. In this latter instance the sheet maybe molded into a cup shape.

In some embodiments of the present invention, the DBF used in an implantuses bone that has had the mineral component removed by ademineralization process that renders the graft malleable and not hard.The bone is then further formed into fibers by cutting along the longaxis such that the collagen fibers within it are maintained in theirnatural fibrous form, as disclosed in U.S. Pat. Nos. 9,486,557 and9,572,912, supra. This material may then be placed into tubes to formthe implant device and to facilitate delivery into the screw hole.

A number of methods of forming cylindrical implants from DBF are alsodisclosed in WO 2016/123583, the entire content of which is hereinincorporated by reference.

In some embodiments, the methods for making the bone fibers includedemineralizing whole bone and subsequently cutting the demineralizedbone in a direction parallel to the orientation of collagen fiberswithin the demineralized bone to form elongated bone fibers. The bonematerial of the present invention is derived from human (allograft) oranimal (xenograft) cortical bone and is processed in such a manner toprovide grafts of high utility based on the controlled geometry of thebone fibers. For veterinary applications bone from the same species.e.g., canine for canine patients (allograft) may be used as well as bonefrom other species (xenograft). It will be obvious to one skilled in theart that fibers other than demineralized bone fibers may be utilized tomake a bone graft of this invention. Such fibers may be made fromresorbable polymers or bioactive glasses or mixtures thereof, and may beused in place of or as an additive to the demineralized bone fibers(DBF). The methods of preparation of the graft provide improvedefficiency and uniformity with reproducible results and decreasedrequirements for equipment and resulting costs. The implant device formsaccording to some embodiments of the present invention do not requirethe addition of exogenous materials to maintain the form of the graft.These improved characteristics will be apparent to one skilled in theart based upon the present disclosure.

The fibers need to have greater than a minimum length to be able tofunction effectively. If they are too short, they will not entangle toform a cohesive dry implant. Also to prevent movement in the cavity postimplantation, and after screw placement, they need to be longer than thepitch of the screw thread so that the screw holds them in place. Theminimum length cannot be precisely defined but is approximately 15 mm(e.g., between 10 and 20 mm). Fibers up to 4 cm in length havesufficient length to provide entanglement and are preferably 500 to 1500microns in width and 50 to 300 microns thick.

It is also important to a number of the applications that the DBF can bedried to render a stiffer implant at the time of implantation.

A further benefit of the DBF fibers is their ability to be processed toform an implant that retains its integrity when wet.

Processing of Fibers.

Processing of the demineralized bone fibers, synthetic polymer fibers,collagen fibers, or resorbable polymer fibers to produce a desired shapeor form of the fibers may be performed using any suitable method.Processing of specifically demineralized bone fibers may be performedusing any suitable method as disclosed herein. To make some of theseforms, the bone fibers may be collected, ideally in their hydratedstate, and compressed using pressure molds, the pressure beingsufficient to form the required shape but not so high as to lose theporosity of the fibrous structure. In some embodiments, the bone fibersare formed using a wet lay technique as is well understood by thoseskilled in the art of nonwoven or paper manufacture. Using a wet laytechnique, the cut bone fibers are suspended in an aqueous solution toform a bone fiber slurry. Any suitable biocompatible aqueous solutionmay be used. Non-limiting examples of biocompatible aqueous solutionsinclude: water, saline, and/or solutions including salts such asphosphate buffered saline (PBS), Ringer's solution, Lactated Ringer'ssolution, and saline with 5% dextrose. In some embodiments of thepresent invention, cut fibers are placed into saline to create a slurryof entangled bone fibers. The bone fiber slurry is suspended over a meshscreen (having holes) and the saline is drained resulting in a wet layprocess, such that a sheet of demineralized bone fibers is formed on themesh screen. The screen is contoured to provide a three-dimensionalshape to the screen such that cylindrical pellets may be directlyproduced, or is flat so that a sheet is produced. The resulting devicesmay be then dried using heat and/or vacuum or other means such aslyophilization (freeze-drying). In some embodiments, prior to drying,the sheet is placed in a mold and compressed to a defined thickness andshape, followed by drying. As discussed herein, density, porosity andoverall dimensions of the resulting product may be controlled usingvarious molds and techniques.

Hydrated fibers may also be simply placed into a cylindrical mold cavityand lightly compressed using a plunger or push rod such as is shown inFIGS. 4, 5 and 6. In these variants features are provided to modify theprofile of the two ends of the cylindrical mold. A set amount of fiberis introduced into a cylindrical mold and the plunger used to compressthe fibers to the required density through control of the depth that theplunger is pushed. Where a plunger has a spike on it, such as is shownin 6 of FIG. 9 the spike may be designed to form a depression, a partialhole, or a hole through the length of the implant. In this latterinstance the implant will be in the form of a tube.

In some embodiments a vacuum oven is used, whereby the application ofvacuum removes moisture and dries the implant.

In some embodiments the heating step is undertaken by placing theimplant in contact with a metal or other high heat-conductivity surfacesuch that the degree of annealing/crosslinking is enhanced at thatsurface.

In other embodiments, the bone fibers are further processed in a seconddrying step that may include vacuum drying and/or lyophilization.

In some embodiments the amount of compression, heating, and drying canbe tailored to modify the rehydration and re-expansion rates. Forexample, with no heating the rehydration is very fast whereas heating ator between 35° to 55° or 45° to 55° C. for approximately one hour causesvery slow re-hydration and re-expansion. In other aspects, the heatingmay occur at any of 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°,45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, or 55° C. By alteringthese processes, bone fiber compositions as disclosed herein may retaintheir manufactured shape during packaging, shipment, unpacking andplacement into the graft site, but after placement into the graft sitethe DBF will begin to absorb moisture rapidly (within 30 seconds orless) and may be completely re-hydrated/re-expanded within approximately2 minutes, preferably being completely re-hydrated/re-expanded within 30seconds.

In other embodiments the bone fibers may retain some moisture and willbe placed in moisture impervious packaging. Furthermore, the dried andmolded bone fiber implant may be sterilized after packaging.Sterilization of the implant may be carried out using any suitablemethod. For example, sterilization may be carried out by electron beamor gamma beam. Alternatively, aseptic manufacture may be used to avoidthe need for terminal sterilization.

In other embodiments, the inventive subject matter also includes asimple mold of the sort shown in FIG. 8 may be used to make DBF sheetsof 0.5 mm to 5 mm thick, where the mold lid may be placed on the mold 17(the mold having holes for drainage of the liquid in the DBF slurry)where the lid is in contact with the DBF after the DBF has been wet laidand may define the degree of compression of the DBF and hence thedensity of the sheet.

A DBF sheet that is dried will have a low wet strength when rehydratedand improvement to the DBF sheet wet strength may be affected by placingthe mold in an oven at 45-55° C. and heat treating the sheet for up to 2hours.

In some embodiments, bone fiber pellets are formed by adding wet fibersdirectly into a cylindrical mold. An example of a cylindrical mold is ametal tube as is shown in FIG. 4. A bone fiber pellet shape is useful asit may be delivered to a graft site using a cannula as commonly used forminimally invasive surgery. The bone fiber pellets are capable ofpassing through a tube. A cylindrical mold is loaded with the fiber. Atamp is used to apply some compression to the fibers. In someembodiments, a fiber loaded cylindrical mold is dried by heat, vacuum,and/or lyophilization. After drying, the bone fiber implant becomes morecohesive and shrinks to a reduced volume. After drying, the bone fiberpellets may be easily expelled out of the mold due to the shrinkage thatoccurs upon drying.

While wet lay techniques may be used for the manufacture of differentshapes from the bone fibers, it will be recognized that any othermolding or forming technique used with textile fibers could be used.Fibers with and without excipients may be directly molded usingcompression into any shape. In some embodiments, excipients may beselected that enhance the lubricity of the implant facilitating deliveryand further reducing and friction or binding during this procedure.

Long cylindrical implants may not be easily produced using aconventional wet lay process. As an alternative method, implants may bewet laid into a mold 12 with two conjoined semi cylindrical depressionshaving drainage holes throughout as shown in FIG. 7. The implants 14 maybe stored in this manner in a flexible storage tray 15 and at the timeof surgery may be folded together to produce a cylindrical implant 16.

Alternatively, semi cylinder implants produced in a mold such as shownin FIG. 7 may be folded together post wet lay and prior to the heattreatment step. At this time the two halves of the cylinder will becomeentangled and bonded to each other.

Alternatively implants for augmentation of screw fixation may be formedin two halves, such that the implant is folded about the part thatbecomes the implant's distal end. A selection of such designs are shownin FIGS. 15a -15 i. The simplest format is a rectangular prism 31.Variants are shown as follows: in FIG. 15b where a central portion 32 isdensified to provide it with increased strength; in FIG. 15c where thecross-section 33 is semi-circular; in FIG. 15d where the rectangularprism is narrower at the center 34; and FIG. 15e where the rectangularprism is both narrower at the center 34 and possesses a semi-circularcross-section 33. FIG. 15f shows a side view cross-section of a drillhole 35 with an implant 31 inserted, the insertion being effected by useof a pusher 36. The implant is longer than is required to fit the hole.FIG. 15g shows a side view cross-section of a drill hole 35 with animplant 31 inserted, the insertion being effected by use of a pusher 36in which the implant 31 is the exact length or about the lengthnecessary to fit in the hole without protruding out of the hole.Additionally, FIG. 15h is an end view looking down the hole to show thatthe implant shown in FIG. 15c forms a space-filling implant wheninserted into the hole. And FIG. 15i is a cross-sectional view of theimplant of FIG. 15e inserted into a tapered hole where the shape of theimplant is designed to be space-filling in a tapered hole.

With continued reference to FIGS. 15a -15 i, implants of these designsmay be fabricated using a wet lay method with a mold that hasdepressions that define the required implant dimensions. The DBF may beheated to a temperature of between 40° and 53° C. for 30 to 150 minutesto dry the implant and to improve the cohesion of the fibers. Afterdrying the individual implants are cut out of the wet lay mold.

Using the implant designs according to embodiments of the presentinvention allows for facilitated insertion of the implant into holes byuse of a pusher that acts upon the fold of the implant, as shown, forexample in FIG. 15 b, 32.

There are particular difficulties that are encountered when trying tomake implants of the size and shape required to be used in augmentationof screw fixation in orthopaedic and spine surgery. The desired orrequired implant dimensions are approximately 2 to 7 mm diameter and 1to 7 cm long. To enable the implant to have sufficient mechanicalintegrity and for the implant to be implantable, the DBF fibers must beof a sufficient size to provide a cohesive implant. The currentlyavailable DBF are approximately 4 cm long and 500 to 1000 microns wideare able to provide the mechanical integrity, however the fiber sizeprovides a difficulty in processing the DBF into the required sizesusing the heretofore-identified manufacturing methods. This problem isexacerbated when the implant is less than approximately 5 mm in diameterand is required to be longer than 1.5 cm. The fabrication of the implantof Example 1 below, while possible, was an extremely time consuming anddifficult process, and is not conducive to an efficient manufacturingprocess. Furthermore, molding parts of the designs shown in FIGS.15a-15i require that the wet laid DBF is wet laid into the grooves ofthe mold rather than across them. If the fibers cross from one implantcavity to another then the fiber will be cut when the part is removedfrom the mold. If this occurs for too many fibers, then the cohesivestrength of the part will be lost. For these reasons, there is a size ofapproximately 5 mm width, below which implants cannot be produced usingthis methodology.

The wet lay process was originally developed for use in paper making andtextiles where the fibers are processed to make a two-dimensional sheetlike product. As the fluid drains the fibers are laid onto the surfaceof the mold and as such are in a plane that is generally parallel to theplane of the sheet being produced. While this process can accommodatesome undulations and be used to make shapes like egg cartons it iswholly unsuitable for the fabrication of cylindrical shapes.

According to embodiments of the present invention, by dispersing fibersin an excess of fluid, the fluid and fibers may be directed into moldsof small diameter and long length. Implants that are about 2 to about 5mm in diameter and about 4 to 5 cm in length have a volume of 0.15 cm³up to 10.0 cm³. Typically, the volume of the implant is about 0.15 cm³up to 2.0 cm³.

Additionally, the length of the implant may be of between 2 cm in lengthup to 10 cm in length depending on the need of the bone repair site. Thelength of the implant may be of between 3 cm and 10 cm in length, 4 cmand 10 cm in length, 4 cm and 9 cm in length, 4 cm and 8 cm in length, 4cm and 7 cm in length, 4 cm and 6 cm in length, or 4 cm and 5 cm inlength. For receiving and fixing a bone screw, the implant (e.g., 31 ofFIG. 15 i, or 68 of FIGS. 30a and 30d ), may have a length correspondingto the length of the bone screw. Accordingly, the length of the implanthaving a cone, tubular, or cannulated shape may have a length suitablefor receiving a bone screw or any bone repair material includingadditional demineralized bone fibers (DBF).

The required mass of DBF to fill those molds is approximately 0.15 gramto 1 gram and may be dispersed in about 20 mls of fluid in a syringe, ina ratio of fibers to fluid as disclosed herein. Dispersion of the fibersin fluid into the molds may be by injection pressure or by vacuum aswell as gravity as needed. Any suitable fluid buffer may be used. Forexample, phosphate buffered saline (PBS) may be used for dispersion ofthe fibers as well as water or any biocompatible buffer or liquid.

In contrast to conventional methods of fabrication, rather than rely ongravitational flow, an elevated pressure is applied to the dilute fiberand fluid dispersion. This forces the fibers to flow down narrowdiameter structures rather than form an entangled clump at the entranceto the mold cavity. Because the fibers are dispersed, they do notcompact when introduced into the mold. Accordingly, the slurrysuspension of fibers is advantageously introduced and place in the moldbecause the fiber suspension is injected or pushed into the mold at arate greater than a gravitational flow, but not so much pressure/forcethat the fibers clump or compact. For example, a 15 ml slurry of a fibersuspension having a ratio as disclosed herein is introduced into a moldin about 1 to 5 seconds. As such, the slurry of fibers are placed orprovided into the mold at a rate from about 3 mls/second up to 15mls/second.

FIG. 16 depicts an apparatus for water- or fluid-assisted injectionmolding of DBF fibers. The required mass of DBF fibers 37 are loadedinto a syringe 38. A suitable fluid (e.g., water, saline, or a bufferedsaline including phosphate buffered saline (PBS) is then added to thesyringe. The distal end of the syringe is then fitted into an adapter 39to which a detachable mold 40 is attached. The mold renders the requireddimensions of the implant to be made, and the mold may be cylindrical,ribbed, and/or tapered. As with conventional injection molding, thecylinder will have a small taper or draft to allow removal of the moldedpart. The mold is tapered towards its distal end and has vents 41 alongits length, and a removable vented end cap 42 to allow for the fluid toegress out of the DBF mixture. The detachable mold is removed after DBFinjection and placed into an oven or lyophilizer for drying. Multiplemolds may be used with one adapter and syringe to allow multiple partsto be fabricated.

In some embodiments of the present invention, the ratio of fluid (e.g.,saline) to DBF may be about 3 mls fluid to 1 gram DBF. In otherembodiments, the ratio of fluid to DBF is about 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28,29, 30, 40, 41,42, 43, 44, 45, 46, 47, 48, 49, or 50 mls fluid to 1 gramof DBF. In still other embodiments, the ratio of fluid to DBF is lessthan about 200 mls fluid to 1 gram DBF. Advantageously, a ratio of fluidto DBF being in the range of between about 3 to 200 mls fluid to 1 gramDBF, 3 to 150 mls, 3 to 100 mls, 3 to 50 mls, 3 to 20 mls, or 3 to 10mls all provide enough fluid to hydrate the DBF to facilitate shapingand forming of the DBF implant into the desired shape while alsoallowing for complete removal of the fluid to produce a dry DBF implant.

In some embodiments of the present invention, water jet assistedinjection molding of DBF fibers is used. As shown in FIG. 17, the DBFfibers 37 are loaded into the hopper 43. The hopper is attached to adetachable mold 40, and the mold is tapered towards its distal end andhas vents 41 along its length, and a removable vented end cap 42. A handoperated water jet 44 is activated to force the DBF from the hopper andinto the mold. The detachable mold is removed after DBF injection andplaced into an oven or lyophilizer for drying.

With reference to FIGS. 30a and 30 d, the disclosed water assistedinjection molding process may also be used to make the DBF implants suchas the screw fixation device 68.

In more specific embodiments, the nozzle of the water jet is of betweenabout 0.1 to 1 cm in diameter. Typically, the nozzle diameter is ofbetween about 1 mm to 5 mm in diameter, and more typically, the nozzlediameter is of between about 2 mm to 4 mm in diameter. The fluid flowrate may be about 1 ml/minute, 30 ml per minute, or preferably up toabout 1000 ml per minute.

The skilled person may easily envisage an apparatus with multiplefunnels leading to multiple molds in a manner analogous to multi-cavityinjection molds as used to fabricate injection molded polymer parts.

The implants of the present disclosure in their dry state may beinserted into a cavity, screw hold, awl hole, or drill hole.Additionally, the implants of the present disclosure may be housed in asyringe or syringe-like insertion device. With the implant in a syringeor syringe-like insertion device, the implant may have lateral stabilitythereby preventing or decreasing bending or buckling of the implantwhile it is being pushed into the surgical site (e.g., the cavity orhole).

In some embodiments of the present invention, entanglement of the DBFmay be increased by stirring the fibers while in a liquid slurry. Bycreating a vortex, fibers are swirled and induced to become entangled.This entanglement results in non-woven ‘ropes’ of fibers that may beextruded and then cut to length and used as is, or further processedinto pellets as described in this disclosure.

For the implants to swell post-implantation so that they aresubstantially space-filling, control of the processing conditions of thefibers may be controlled. For example, in some embodiments, the fibersare compressed, heated, and/or otherwise dried in order to render thefibers in a compact state such that upon wetting, the fibers are able toexpand and swell.

In some embodiments of the present invention, an implant system packageor implant kit includes the cylindrical molds and plunger as shown, forexample, in FIG. 4.

Excipients and Additives.

Additives are contemplated to modify biological or other properties ofthe implant according to embodiments of the present invention.Non-limiting examples of additives include growth factors such as bonemorphogenetic proteins (BMPs), including BMP-1, BMP-2, BMP-3, BMP-4,BMP-5, BMP-6, BMP-7, BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13,BMP-15, BMP-16, BMP-17, and BMP-18; Vascular Endothelial Growth Factors(VEGFs), including VEGF-A, VEGF-B, VEGF-C, VEGF-D and VEGF-E; ConnectiveTissue Growth Factors (CTGFs), including CTGF-1, CTGF-2, and CTGF-3;Osteoprotegerin, Transforming Growth Factor betas (TGF-βas), includingTGF-β-1, TGF-β-2, and TGF-β3, and inhibitors for tumor necrosis factor(e.g., anti-TNF-α). Morphogens may also include Platelet Derived GrowthFactors (PDGFs), including PDGF-A, PDGF-B, PDGF-C, PDGF-D, and GDF-5;rhGDF-5; and LIM mineralization protein, insulin-related growth factor-I(IGF-I), insulin-related growth factor-II (IGF-II), fibroblast growthfactor (FGF) and beta-2-microglobulin (BDGF II), as disclosed in theU.S. Pat. No. 6,630,153, the entire contents of which is incorporatedherein by reference. The polynucleotides encoding the same may also beadministered as gene therapy agents. The preferred bioactive substancesare the recombinant human bone morphogenetic proteins (rhBMPs) becausethey are available in relatively unlimited supply and do not transmitinfectious diseases. In some embodiments, the bone morphogenetic proteinis a rhBMP-2, rhBMP-4, rhBMP-7, or heterodimers thereof. BMPs areavailable from Wyeth, Madison, N.J., and may also be prepared by oneskilled in the art as described in U.S. Pat. No. 5,366,875 to Wozney etal.; U.S. Pat. No. 4,877,864 to Wang et al.; U.S. Pat. No. 5,108,922 toWang et al.; U.S. Pat. No. 5,116,738 to Wang et al.; U.S. Pat. No.5,013,649 to Wang et al.; U.S. Pat. No. 5,106,748 to Wozney et al.; andPCT Patent Nos. WO93/00432 to Wozney et al.; WO94/26893 to Celeste etal.; and WO94/26892 to Celeste et al., the entire contents of all ofwhich are herein incorporated by reference.

Oxygenating additives such as perfluorocarbons may be used to furtherenhance the bone formation and healing of the DBF material in theimplant of the present disclosure. In some embodiments, the bone repairDBF implant composition includes oxygenating materials such as aperfluorocarbon (PFC). In some embodiments, the DBF implant compositionincludes oxygen generating compounds such as peroxides (e.g., hydrogenperoxide, magnesium peroxide, calcium peroxide), perchlorates (e.g.,sodium perchlorate, potassium perchlorate), percarbonates (e.g., sodiumpercarbonate), or perborates (e.g., sodium perborate).

For additional benefits, cancellous or cortical bone chips and/ordemineralized cancellous or cortical bone chips may be added to the DBF.In addition to or alternatively to the bone chips, mineralized bonefibers may be added to the DBF. In addition to bone chips, mineralizedbone fibers or alternatively, calcium phosphate, tri-calcium phosphate,hydroxyapatite, or other synthetic bone graft materials may be added tothe DBF.

According to some embodiments of the present invention, introduction ofan implant for screw augmentation into a patient is accomplished byplacing the implant into a hole that has been drilled to receive ascrew. The implant is sized to fit the hole to be repaired and to bespace filling, i.e., the implant is of approximately the same length anddiameter as the hole. The implant may be placed in the hole directly byhand or may be placed by use of a delivery instrument having acylindrical element to hold the implant with a plunger to expel it.Accordingly, the delivery instruments may be cannulated.

In some embodiments of the present invention, the implant is longer thanthe depth of the hole to be treated and in these instances the surgeonmay cut the implant to a desired length.

Forming an indentation into the end of the implant designed to receivethe screw may facilitate central placement of the screw. Additionally,the implant may be cannulated or tubular to further facilitate screwplacement over a guide wire.

In some embodiments of the present invention, implants are formed andstored in tubes. To facilitate loading into the end of the delivery tubea recess is formed in the end of the elongated member (e.g., cannula) tohold the storage tube in correct alignment.

In some embodiments a plurality of implants are stored in a holder thatis configured to attach to a delivery tube to allow easy deployment ofimplants.

The delivery tube may be straight or curved. In the latter instance theplunger will be flexible, being made of any suitable material, forexample, nitinol wire or braided nitinol wire.

The DBF implant may be shaped with a convex proximal end and concavedistal end by the push rod. Alternatively, implants may be introduced byseparate means into the end of the delivery tube. In some instances,implants having a pellet shape may be easier to introduce into deliverytubes.

At the time of surgery, prior to implantation, a small amount of anysuitable water-soluble contrast agent may be injected into the implantto provide visualization during implantation. An example of awater-soluble contrast agent is Iopamidol.

At the time of surgery and prior to implantation, a small amount ofsterile water, phosphate buffered saline, bone marrow aspirate, and/orblood may be injected into the implant to hydrate the implant.

EXAMPLES

The following examples use cortical human bone. As discussed herein,either human or animal bone may be used as a source of cortical bone.Fibers were produced using the methodology as described in U.S. Pat.Nos. 9,486,557 and 9,572,912, supra.

Example 1

1 ml disposable plastic syringes were used as a mold. The plungers wereremoved and 0.25 grams of DBF were introduced into the end of thesyringe and the plunger used to lightly compress the fibers to a lengthof approximately 4 cm. The plungers were removed and the tip of thesyringe cut off using a scalpel. The implants were vacuum driedovernight at 27° C. The resultant implants were approximately 4.5 mm indiameter

Example 2

Three implants from Example 1 were used to test for augmentation ofscrew pull out. A Sawbones 10 pores per inch foam that is frequentlyused to test screw pull out as a surrogate for osteopenic bone was used.Six 5 mm diameter holes were drilled in the foam block. Implants fromexample 1 were placed in three of the holes. 5.5 mm pedicle screws wereinserted into the six holes. An MTS tensile test machine was used torecord the force required to pull the screws out of the holes. The dataobtained are shown in Table 1 below.

TABLE 1 Peak Force (N) Control Augmented Test 1 346 764 Test 2 338 868Test 3 290 778 Average 325 803

Example 3

15 grams of DBF fiber were wet laid in a 10 cm×11 cm flat mold toproduce a sheet of DBF. The mold was heated at 55° C. for two hours tobond the fibers and dry the sheet. The sheet was approximately 1 mmthick. A portion of the sheet would be suitable for use in augmentingACL or rotator cuff fixation.

Example 4

A portion of the sheet of Example 3 was cut to the shape of the tibialtray from a knee arthroplasty, hydrated and pressed onto the surface ofthe porous coated tibial tray.

Example 5

A portion of the sheet of Example 3 approximately 3 cm by 1 cm washydrated and wrapped around the threaded portion of a 6 mm diameterpedicle screw. The DBF conformed to the surface of the screw.

Example 6

An apparatus to make implants using a water assisted injection molding(WAIM) was fabricated according to the schematic shown in FIG. 16. A 20ml syringe with its distal end removed was placed in a 3D printedadapter. Three detachable mold sizes were used, each 5 cm long withdiameters of: 3.5 mm decreasing to 3 mm; 4.5 mm decreasing to 4 mm; and5.5 mm decreasing to 4.5 mm. DBF was placed in the 20 ml syringe and thesyringe filled with PBS. The end of the syringe was placed in theadapter and the plunger pressed down to inject the DBF into the mold.DBF quantities used were 0.45 gram, 0.6 gram and 1.05 gram for the 3.5,4.5 and 5.5 mm diameters respectively. After molding the molds wereplaced in a vacuum oven and dried under vacuum with a 0.5 L/min air flowovernight. After removal of the end caps the dried implants could besimply removed by pushing from the molds. The implant diameters wereapproximately 0.75 mm less in diameter than the mold diameter.

Example 7

A portion of the sheet from Example 3 was cut into two pieces each 2cm×5 cm with a slot cut in it as shown in FIG. 25 a. The sheets werethen rehydrated and using four 3 mm diameter rods the cruciate form ofFIG. 27a was formed. After drying the implant is shown in FIG. 27 b.This implant was suitable for use in augmenting the fixation of an adgraft.

Example 8

A portion of the sheet from Example 3 was cut into one pieceapproximately 2 cm×5 cm. The sheet was then rehydrated and shaped usingtwo 3 mm diameter rods and then redried. The implant of FIG. 27c wasformed. This implant was suitable for use in augmenting the fixation ofa two strand ad graft.

While the present invention has been illustrated and described withreference to certain exemplary embodiments, those of ordinary skill inthe art will understand that various modifications and changes may bemade to the described embodiments without departing from the spirit andscope of the present invention, as defined in the following claims.

Additionally, although relative terms such as “outer,” “inner,” “upper,”“lower,” “below,” “above,” “vertical, “horizontal” and similar termshave been used herein to describe a spatial relationship of one elementto another, it is understood that these terms are intended to encompassdifferent orientations of the various elements and components of thedevice in addition to the orientation depicted in the figures (Figs.).

What is claimed is:
 1. A composition, comprising an implant for bonerepair, the implant comprising: a plurality of fibers selected fromdemineralized bone fibers (DBF), biocompatible polymer fibers, collagenfibers, and/or resorbable polymer fibers; wherein the plurality offibers form a shape of a cylinder, a tube, a cannulated cylinder, atruncated cone, a cannulated truncated cone, a truncated cone with aflared end, or a cannulated truncated cone with a flared end, tube witha flared end, or a truncated cone shape, wherein the implant has aproximal end and a distal end, and wherein the flared end is at theproximal end of the implant.
 2. The composition of claim 1, wherein theplurality of fibers comprise demineralized bone fibers (DBF).
 3. Thecomposition of claim 1, wherein the implant has a volume of between 0.15cm³ to 10 cm³.
 4. The composition of claim 1, wherein the implant has alength of between 1 cm to 10 cm.
 5. The composition of claim 1, whereinthe flared end comprises an indent for receiving a bone screw.
 6. Thecomposition of claim 1, wherein the implant is dehydrated.
 7. A methodof augmenting fixation of a screw in a bone with the implant of claim 1,the method comprising: optionally placing a guide wire to define aposition in the bone for the screw; inserting or providing the implantto a cavity in the bone; and inserting or providing the screw into theimplant.
 8. The method of claim 7, wherein when the guide wire is used,the providing the implant comprises placing the implant on the guidewire through the cannulated, tubular, or cone shape of the implant andmoving the implant along the guide wire into the cavity.
 9. The methodof claim 7, wherein the moving the implant along the guide wirecomprises using an awl, a pusher, a tap, and/or a drill.
 10. The methodof claim 7, wherein the cavity in the bone is formed using an awl, apusher, a tap, and/or a drill.
 11. A method of augmenting fixation of ascrew in a bone with the implant of claim 1, the method comprising:placing a guide wire to define a position in the bone for the screw;inserting or providing the implant to a cavity in the bone; andinserting or providing the screw into the implant.
 12. The method ofclaim 11, wherein the inserting or providing the implant or the screwcomprises using a cannulated instrument.
 13. The method of claim 11wherein the inserting or providing the implant comprises an open-endedsyringe comprising the implant.
 14. A method of fabricating the implantof claim 1, the method comprising: dispersing the plurality of fibers ina fluid; wherein the plurality of fibers and the fluid are in a ratio ofbetween about 1 gram of fibers to about 3 mls to 50 mls of the fluid;and providing the dispersed plurality of fibers with pressure into avented mold thereby draining the fluid from the mold.
 15. The method ofclaim 14, further comprising heating the plurality of fibers in the moldat or between about 35 to 55 degrees Celsius.
 16. The method of claim14, wherein the plurality of fibers comprise demineralized bone fibers,biocompatible polymer fibers, collagen fibers, and/or resorbable polymerfibers.
 17. The method of claim 14, wherein the plurality of fibers arelyophilized.
 18. A kit for augmenting fixation of a screw in a bone withan implant, the kit comprising: the implant of claim
 1. 19. The kit ofclaim 18, further comprising: a guide wire; an awl or a tap; and/or ascrew to be place in the bone to be repaired.
 20. The kit of claim 19,wherein the guide wire and the awl or the tap are disposable.